For better or worse! Dax Shepard's wife Kristen Bell went to great lengths to help her husband before he filmed this year's This Is Where I Leave You. Shepard admitted during Conan on Monday, Oct. 13, that the Veronica Mars alum helped him get cleaned up for his "graphic full nude scene."

"It was incredibly nerve-wracking and I don't want to put you in a box here, but I think we both do suffer from tall white guy syndrome, where your back just goes into your legs," Shepard, 39, told host O'Brien. "There's really no butt cheeks there."

In the film, Shepard's sleazy character Wade Beaufort (spoiler alert!) sleeps with Jason Bateman's on-screen wife Abigail Spencer. In one bed scene, he has to show off his bare bum.

The Parenthood star said he did a lot of lunges and squats to get in shape for the revealing moment, but his preparation didn't stop there. He also asked his wife Bell to, er, shave down there.

"My deep fear was that it would look like a werewolf trying to escape my butt crack," Shepard said. "So I asked Kristen — the beautiful Kristen Bell that people can already not understand why she's with me."

"She's the only person I would feel comfortable — well, I didn't even feel comfortable with her doing it," he joked. "It was a terrible experience."

Bell, 34, who is expecting the couple's second child, used an "off the shelf" electric razor to help Shepard in his time of need. To ease the awkwardness, she hummed a 1980 classic from the band Lipps Inc.

Shepard sang the tune on Conan, which led Andy Richter to point out the obvious. "Yeah, well, she took a trip to 'Funkytown!'"

Watch the laugh-out-loud video now!